Well, as SCKing said, it's an anthology of K-On! strips by other mangaka. Some of them are good, some are weird, some are kinda dumb. If you're a fan of K-On!, you should give it a read. If nothing else, it's fun to see other people's take on a manga you enjoy If you're not a K-On! fan, well, then I'm sure you won't like this at all, either

If your going into this thinking your going to get the same fill of K-On you get from the original, go jump off a rock. This an anthology, thus nothing like the real manga other than the setting. The author's did a decent job in the least, and some of it was funny; yet as I've said, the original will always be just that.